The only stupid question is the question that is never asked.
- Ramon Bautista
Hello, there should be a couple of ways to achieve this effect, but here's one possible and simple solution which I hope that fits your requirements, in which I make use of the Lerp node:
And the result as you set the slider from 0 to 1, and back to 0:
The problem here is that I don't want the additive effect which is why I had to make it black on the background where the image has to be added.
Basically what I want is a way to just put and image on top of another with transparency based on the image alpha channel. As far as I can see the only two ways of mixing two images is using either add or multiply neither block out the background completely hence the black circle on the background.
Have you had the chance to rate and review Amplify Shader Editor? It would be awesome if you could share your experience with the Unity community, every bit helps and your feedback is extremely valuable to us.
Feel free to get back in touch if you have further issues or questions, thank you!